best thing you can do is get a degreaser but not a heavy duty one. Turn the car on for a minute or two and let it warm a little bit and turn it off. then make sure you cover the vitals (ecu, alternator, angel eyes, hid box, etc) with plastic grocery bags. spray it all over and let it sit for a minute. then take a hose with cool, slow running water and wash everything off. Take some wd40 and dont spray it, use a terry cloth and wipe it in so there isnt any clogs of residue. Another good tip is you can also use the degreaser to clean your plastic wheel wells. Leaves it like if you just got the car from the dealership.